Slide rule



1,581,567 Apfll 20 1926' J. E. ESHBAUGH sLIpE RULE Filed June e, 192s \ZOU lvl

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INVENTOR JESSE E. [5h/BAUM.

Patented Apr. 20,

UNITED y stares mensenmassa, or marron, omo.

emma auna.

Application flied -June 9, 1923. 4 Serial No. 844,475.

special type 'having lo rithmic scales whichv represent volumes to, used in a computation.l The main ob'ect of my invention is to provider a. slide ru e of this type in which four loglarithmic scales are used and in whicht ree of these scales read from left to right while the fourth' scale reads from right to left so that a computation can be made bg means of asingle move of the slide.

Furt er objectsaremore fully set foi-th in the attached specification and claims and in the'drawings in which:

Fig. 1 is la plan view of oneform of m y invention, in which thesca'les represent vo ume, temperature, time and volume per unit time,and in which the temperature isgiven in absolutevdegrees. Fig. 2 is a second, form of my 'invention in which the temperature is given in degrees ceitigrade.; gul h n 'testing oxygen re ators o t et used to regulate the supply of oxygen an oxygen tank to a pilot of an airplane, the volume displacement method is used.

The formula used in this method of testing.

the quantity of oxygen emitted by. the reo'ulator per zunit of time, is expressed as ioh lowsswhich F=litersuof oxygen emitted per minute; vztotalvolu'me ofthe` test chamber in liters; T-:temperature oi the regulator; tztime in seconds for the pressure in.the test chamber to cha e 2 centimeters of mercury. The values T,-

and t are determined vfrom which thefourth variable may be computedandthis computation is quite readily made by a 'slide'rule as set forth in either Fig. l or Fig. 2.

In Fig. l', a slide rule is shown having ai central slider and a main base oit' a.v con-4 ventional construction.- The base is provided with alogarithmic scale Zf which is suitably marked by, indices from the left the-absolute degrees temperature in the computation". A-scale-a which reads from left,

to right is provided on the slider adjacent lto the'vscale b and indicates the volume of the test chamber. A scale ,c on the bottom of the slider reads fromlleft tQ right and indicates the time for the pressurel inthe test chamber to change .two centimeters of mercury. The fourth scale which is on the rule base reads from' right to left contrary to the other threev scales, and indicates the liters of oxygen emitted per minute. All

four of these scales are of the same -loga'rithf mic value.

In 'order to determine the value of F for any computation, the value of T which was determined during the'test, is located on the upper scale. The slider is then moved until the value of V which was determined during the test, is opposite yto this Value of T. The slider has thereby been set so that opposite the value of t which vwas determined during the test, the corresponding -value of F may be read. It will be necessary to'have these scales so related that the desired values of F, V, t and F come within the working portions oi the scales and it is not at all necessary and it is indeed oftentimes impractical to have scales all starting from Z or from the same number of a did'erent value. The relative positions of the scales may be determined by making one computation or calibration 'and all other computations or calibrations will then be absolutely correct:-

Itwill be obvious that such a slide rule can be applied for solving other computations having a -somew at similar formula and it is not desired to limit myseli tothe particular embodiment .which has been shown by Way of illustration.,`

I claim- A slide vrule having a slide and a base, bearing two sets of logarithmic scales one set of two di'erent scales u on each side oi its longitudinal center, being on the slide, a scale b of the same set bein upon the base, all of said scales having iderent origins, and scales c and d of the otherset being upon the slide and base respectively,three or said scales reading in the vsamedirection and the fourth 'reading oppositely; said scales being so re- V :sl i to the right. This scale is used to 'indicate lated that, a cd at any Smg e posmon o whereof I aiiix m s1 JESSE EESH A a sca e. a oi one set nos A 

